1. Field of the Invention
The present invention relates to a brake hydraulic pressure control device for use in a brake system for vehicles.
2. Discussion of the Related Art
Heretofore, as brake hydraulic pressure control devices, there has been known one which is described in United States patent application publication No. US 2005/0265852 A1 (equivalent of Japanese unexamined, published patent application No. 2006-008107). As shown in FIGS. 2 and 3 of the publication, in the brake hydraulic pressure control device, an electric motor 50, a shutoff valve 17, a pressure reducing side proportional control valve 18 and a hydraulic pressure sensor (pressure sensor) 19 is concentrically arranged on one surface 30a of a housing 30. In this arrangement, the hydraulic pressure sensor 19 is arranged out of the area for the electric motor 50. In other words, the hydraulic pressure sensor 19 is not arranged between the electric motor 50 and the housing 30.
Also, as brake hydraulic pressure control devices, there has been known another which is described in Japanese unexamined, published patent application No. 11-208440. As shown in FIGS. 1 to 3 of the Japanese application, in the brake hydraulic pressure control device, pressure reducing control valves 1-4, pressure increase control valves 5-8, switching valves 9 and 10, a pressure sensor 21 are provided on one surface of a housing 16, while an electric motor 15 is provided on the other surface opposite to the one surface. The pressure sensor 21 provided there is one only.
In the brake hydraulic pressure control device described in the United States publication, the electric motor 50, the shutoff valve 17, the pressure reducing side proportional control valve 18 and the hydraulic sensor (pressure sensor) 19 are juxtaposed on the same single surface. This configuration requires the surface to be large in area and hence, gives rise to a problem that the housing and hence, the brake hydraulic pressure control device is increased in dimension.
Further, in the brake hydraulic pressure control device described in the Japanese application, the pressure reducing control valves 1-4, the pressure increase control valves 5-8, the switching valves 9 and 10, the pressure sensor 21 are provided on the surface different from the surface mounting the electric motor 15 thereon. This configuration can downsize the housing or the entirety of the device in comparison with the brake hydraulic pressure control device in the United States publication. However, where a plurality of pressure sensors are to be provided, it would become difficult to sufficiently downsize the housing and hence, the entirety of the device.